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Deep levels in low‐energy electron‐irradiated 4H‐SiC
Author(s) -
Carlsson P.,
Son N.T.,
Beyer F. C.,
Pedersen H.,
Isoya J.,
Morishita N.,
Ohshima T.,
Janzén E.
Publication year - 2009
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.200903060
Subject(s) - electron paramagnetic resonance , irradiation , deep level transient spectroscopy , materials science , photoexcitation , electron beam processing , vacancy defect , acceptor , ionization energy , ionization , analytical chemistry (journal) , electron , atomic physics , chemistry , nuclear magnetic resonance , optoelectronics , crystallography , silicon , ion , physics , organic chemistry , chromatography , quantum mechanics , nuclear physics , excited state , condensed matter physics
Deep levels introduced by low‐energy (200 keV) electron irradiation in n‐type 4H‐SiC epitaxial layers grown by chemical vapour deposition were studied by deep level transient spectroscopy (DLTS) and photoexcitation electron paramagnetic resonance (photo‐EPR). After irradiation, several DLTS levels, EH1, EH3, Z 1/2 , EH5 and EH6/7, often reported in irradiated 4H‐SiC, were observed. In irradiated freestanding films from the same wafer, the EPR signals of the carbon vacancy in the positive and negative charge states, V C + and V C ‐ , respectively, can be observed simultaneously under illumination with light of certain photon energies. Comparing the ionization energies obtained from DLTS and photo‐EPR, we suggest that the EH6/7 (at ∼ E C – 1.6 eV) and EH5 (at ∼ E C – 1.0 eV) electron traps may be related to the single donor (+ | 0) and the double acceptor (1– | 2–) level of V C , respectively. Judging from the relative intensity of the DLTS signals, the EH6/7 level may also be contributed to by other unidentified defects. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)